Flow cytometry: An improved method for the selection of highly productive gene-amplified CHO cells using flow cytometry

2001 ◽  
Vol 74 (5) ◽  
pp. 435-442 ◽  
Author(s):  
Tomohiro Yoshikawa ◽  
Fumi Nakanishi ◽  
Yuki Ogura ◽  
Daisuke Oi ◽  
Takeshi Omasa ◽  
...  



Author(s):  
Xinshui Yu ◽  
Zhaohui Yang ◽  
Kunling Song ◽  
Tianxiang Yu ◽  
Bozhi Guo

The distribution and parameters of the random variables is an important part of conventional reliability analysis methods, such as Monte Carlo method, which should be known fist before using these methods, but it is often hard or impossible to obtain. Model-free sampling technique puts forward a method to get the distribution of the random variables, but the accuracy of the extended sample generated by it is not enough. This paper presented an improved model-free sampling technique, which is based on Bootstrap methods, to increase the accuracy of the extended sample and decrease the iteration times. In this improved model-free sampling technique, the method of the selection of initial sample points and the generation of iterative sample is improved. Meanwhile, a center distance criterion, which considers the local characteristics of the extended sample, is added to the generating criterion of dissimilarity measure. The effectiveness of this improved method is illustrated through some numerical examples.



2014 ◽  
Vol 602-605 ◽  
pp. 3177-3180
Author(s):  
Wei Ping Cui ◽  
Li Juan Du

In this paper, through comparison and analysis of various wavelet denoising methods, a new threshold function is constructed, and the selection of threshold is improved. Signal denoising simulation is made by the software MATLAB, the results show that the improved method is superior to the traditional method, and obtain a better denoising effect.



1964 ◽  
Vol 82 (3) ◽  
pp. 608-610 ◽  
Author(s):  
Charles E. Helmstetter ◽  
Donald J. Cummings


1992 ◽  
Vol 76 (2) ◽  
pp. 275-275
Author(s):  
Guinet Françoise ◽  
Louise Anne ◽  
Antoine Jean-Claude ◽  
Roth Charles
Keyword(s):  


1971 ◽  
Vol 11 (01) ◽  
pp. 23-37 ◽  
Author(s):  
C. Petrauskas ◽  
P.M. Aagaard

Abstract An improved method is presented for selecting offshore structure design waves by extrapolating historical storm data to obtain extreme value statistics. The method permits flexibility in choice of distribution functions through use of computerized procedures, estimates extrapolated wave-height procedures, estimates extrapolated wave-height uncertainty due to small sample size, and includes criteria for judging whether or not given wave-height values can be represented by one or more of the distributions implemented in the method. The relevance of uncertainty to selection of design-wave heights is discussed and illustrated. Introduction The problem of selecting design-wave heights for offshore platforms has many facets, ranging from the development of oceanographic data to the selection of the prudent level of engineering risk for a particular installation. This paper deals only with part of the problem; it describes an improved method for using the small available amount of wave-height information to estimate the extreme value statistics and associated uncertainties for the large storm waves that have a very low probability of occurrence. probability of occurrence. Hindcast wave-height information for design-wave studies usually covers a period of historical record that is shorter than the return period selected for acceptable engineering risk. Return periods commonly used for selection design waves are 100 years or more, but good meteorological data, on Which the calculated wave heights are based, can rarely be obtained for periods covering more than 50 to 60 years. As a consequence, extrapolations to longer return periods are necessary. Present methods for making the extrapolation employ probablistic models through the use of special probability graph papers on which a family of distribution functions plot as straight lines. The wave heights are plotted vs their "plotting-position" return period, and a straight line fitted to the plotted data is extended beyond the data to estimate extreme wave heights for return periods of interest. The methods are described in periods of interest. The methods are described in numerous technical papers and books; Refs. 1 through 5 are examples. The shortcomings of the present commonly used methods are:the straight line drawn through the data is in most cases visually fit to the data, thus is subject to error; andno information is available on the uncertainty of the resulting extrapolation. These shortcomings have been discussed by many authors and many of their concepts influenced this study. The improved method presented in this paper offers:greater flexibility in the choice of distributions through computerized procedures,guidelines for picking the "best" distribution from several implemented in the method, andprocedures for estimating the uncertainty of procedures for estimating the uncertainty of extrapolated wave heights. CONDENSED CONCLUSIONS Procedures described in this paper for extrapolating hindcast storm-wave heights and estimating uncertainty intervals to the extrapolated values are recommended as aids in selecting the design-wave height. The results of the extrapolating procedure and related uncertainty considerations procedure and related uncertainty considerations are only aids to help the engineer assess the risks associated with his design. The actual selection of the design-wave height is a matter of engineering judgment. The choice is subjective and will vary according to the risk chosen for the design. Further consideration of ways to decrease the span of be uncertainty intervals is warranted. Increasing the number of years represented in the sample along with the number of storms is a direct way to decrease the span. In the areas of the world having poor weather records the sample size will be marginal for many years to come. SPEJ P. 23



2020 ◽  
Vol 9 (7) ◽  
pp. 2036
Author(s):  
Jaroslaw Bilinski ◽  
Mikolaj Dziurzynski ◽  
Pawel Grzesiowski ◽  
Edyta Podsiadly ◽  
Anna Stelmaszczyk-Emmel ◽  
...  

Methods of stool assessment are mostly focused on next-generation sequencing (NGS) or classical culturing, but only rarely both. We conducted a series of experiments using a multi-method approach to trace the stability of gut microbiota in various donors over time, to find the best method for the proper selection of fecal donors and to find “super-donor” indicators. Ten consecutive stools donated by each of three donors were used for the experiments (30 stools in total). The experiments assessed bacterial viability measured by flow cytometry, stool culturing on different media and in various conditions, and NGS (90 samples in total). There were no statistically significant differences between live and dead cell numbers; however, we found a group of cells classified as not-dead-not-alive, which may be possibly important in selection of “good” donors. Donor C, being a regular stool donor, was characterized by the largest number of cultivable species (64). Cultivable core microbiota (shared by all donors) was composed of only 16 species. ANCOM analysis of NGS data highlighted particular genera to be more abundant in one donor vs. the others. There was a correlation between the not-dead-not-alive group found in flow cytometry and Anaeroplasma found by NGS, and we could distinguish a regular stool donor from the others. In this work, we showed that combining various methods of microbiota assessment gives more information than each method separately.



Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1535-1535
Author(s):  
Suzana M. Zorca ◽  
Emma C. Josefsson ◽  
Viktoria Rumjantseva ◽  
John H. Hartwig ◽  
Karin M. Hoffmeister

Abstract We previously reported that the lectin domain of the αMβ2 receptor on macrophages mediates the rapid clearance of transfused washed murine platelets which have been refrigerated for 2 hrs in the absence of plasma. The clearance is mediated by the recognition of exposed βN-acetylglucosamine (β-GlcNAc) residues on N-linked glycans of clustered platelet GPIbα molecules. Covering the exposed β-GlcNAc residues on GPIbα N-linked glycans via galactosylation prevents the clearance of chilled murine platelets from the circulation. The role of N-linked glycans in platelet function and survival is unclear. To dissect the role of N-linked glycosylation of GPIbα on the binding of von Willebrand factor (vWf), we use human platelets and Chinese Hamster Ovary (CHO) cells, stably expressing human GPIbα/βand GPIX. Deglycosylation of platelet GPIbα N-liked glycans was achieved using the enzyme peptide-N-glycosidase F (PGNaseF), specific for complex N-linked glycans. In agglutination assays using platelets incubated with and without PNGaseF for 16hrs at 37°C, we observed 30-40 % less agglutination in response to ristocetin for platelets depleted of N-linked glycans with PNGaseF. Additionally, a 30 % reduction in vWf binding to PNGaseF-treated platelets compared with control platelets was measured by flow cytometry, using a FITC-conjugated mAb that detects surface-bound vWf. In CHO cells, GPIbα N-linked oligosaccharides were manipulated by adding swainsonine or tunicamycin, two inhibitors of N-linked oligosaccharide synthesis in the Golgi. vWf binding to platelets or to CHO cells was studied by aggregometry or by light microscopy to establish the fraction of CHO-cell aggregates. As was the case with platelets, vWf-dependent aggregation of CHO cells expressing GPIb-IX decreased three fold in response to botrocetin, but only following complete N-linked glycans depletion with tunicamycin. In contrast, partial N-linked carbohydrate modification with swainsonine did not significantly alter aggregate formation in CHO- cells expressing GPIb-IX. Complete inhibition of N-linked glycosylation decreased botrocetin-induced vWf binding to CHO- cells expressing GPIb-IX by ~50%, as determined by flow cytometry. No change was observed following swainsonine treatment. Surface expression of GP1bα remained unchanged after both tunicamycin and swainsonine treatment, and with PGNaseF treatment of platelets. These results confirm that 1) N-linked glycans are not required for GPIbα surface expression, and 2) indicate that N-linked glycans likely play a role in vWf binding to platelet GPIbα.



2009 ◽  
Vol 91 (4) ◽  
pp. 1285-1292 ◽  
Author(s):  
Christiaan F. Hoogendijk ◽  
Theunis F. Kruger ◽  
Patric J.D. Bouic ◽  
Ralf R. Henkel


2007 ◽  
Vol 71A (8) ◽  
pp. 599-604 ◽  
Author(s):  
José I. Martínez-Ferrandis ◽  
Miguel A. Soriano ◽  
Alicia Martínez-Romero ◽  
Guadalupe Herrera ◽  
Andrés Cervantes ◽  
...  


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